In recent years, there have been proposed and developed various transfer drive mode switching control technologies. A transfer drive mode switching control system capable of providing a fail-safe function and a self-diagnosis function under partially failed transfer drive mode switching control system conditions, has been disclosed in Japanese Patent Provisional Publication No. 2001-280491 (hereinafter is referred to as “JP2001-280491”). The main purpose of the drive mode switching control system of the transfer device disclosed in JP2001-280491, is to prevent an automotive vehicle from being conditioned in an undrivable state occurring due to a shift motor kept in a neutral (N) position under partially failed transfer drive mode switching control system conditions, in particular, a drive mode position sensor failure. Actually, the transfer-device drive mode switching control system of JP2001-280491 allows switching to a drive mode position except the N position by activating the shift motor, but inhibits switching to neutral, if the drive mode position sensor is failed. Thereafter, the shift motor remains deactivated and stopped.